1. Field of the Invention
The invention relates to the field of wireless communication. More specifically, the invention relates to a method for receiving emergency information, in particular local emergency information. The invention also relates to system and method for providing such emergency information.
The new millennium has shown various instances of disasters, ranging from world events such as the attacks in the United States on Sep. 11, 2001 to the tsunami on Boxing Day 2004 in the Asia-Pacific region to many local events. Emergency warning systems are crucial in such situations as well as in other emergency cases, including large fires and earthquakes.
Previously, people were alerted to the existence of an emergency situation by audible and visual alarm systems. These systems, however, did not inform people how to act in such situations. Although evacuation plans are normally in place, many people fail to know these plans in sufficient detail to apply them in critical situations. Dynamic changes in such situations may also require changes in evacuation plans that in turn need to be communicated to the public.
Today, virtually everyone possesses or can be in contact with someone who possesses a mobile telecommunication device. Ready availability of mobile communications devices can be a public service asset to provide critical information to the public during emergency situations.
As an example, ETSI is currently attempting to standardize emergency communications in TS 102 182. One of the ideas is to use a cell broadcast service (CBS) allowing broadcasting of messages to mobile phones of a large number of citizens in a specific location within a short predictable period of time. It is the aim to provide an alert to 50% of the citizens in the relevant area within 3 minutes and to 97% of the citizens in that area within 5 minutes. Due to the nature of the broadcast a single message can reach all mobile phones, including those of roamers. Messages can be repeated for those who enter the area later or have missed previous messages. Cell broadcast uses a dedicated channel, so the functionality will generally be available, even if voice and data traffic in the network are congested. The CBS system allows providing information transmission concerning the emergency situation to people in the relevant area.
The area for the CBS system can be as small as one cell. However, such a cell may be larger than the area relevant for the disaster. Moreover, one or more cell areas will rarely exactly match the relevant areas for providing the emergency information. Finally, within a cell, the relevant emergency information may be different for different positions within that cell. As an example, people being on several floors of a building may require different emergency information relating, e.g., to the use of elevators.
2. Description of the Prior Art
US Patent Publication No. 2007/0207771 describes a system and method that enables distribution of public warning information using network infrastructure. Public warning messages are received by a wireless receiver coupled to a network. The wireless receiver broadcasts a message to users on the network responsive to receiving a public warning message.
Broadcasting on a local network is not straightforward. Broadcasting of significant amounts of data is generally not possible for such networks. Typically, only data such as a cell ID, an SSID etc. are broadcast. Furthermore, the cells of a local network are typically of limited size and broadcasting is considered to be a waste of resources if the probability of presence of people in such a cell is low. Moreover, broadcasting requires judgment when to start and stop the broadcast transmission.
There exists a need in the art for an improved emergency notification method and system that enables rapid communication of locally relevant information despite network traffic congestion.